Classification of Hazardous Locations for an Electrical Installation

Contents

Conditions

Class

Division

flammable gas or vapors

present under normal operating conditions

I

1

flammable gas or vapors

occurs frequently due to one or more causes (repair; leakage; maintenance)

I

1

flammable gas or vapors

breakdown or faulty operation of equipment

I

1

flammable gas or vapors

within closed containers or systems

I

2

flammable gas or vapors

controlled by positive mechanical ventilation but vulnerable to failure

I

2

flammable gas or vapors

adjacent to Class I, Division 1 site

I

2

combustible dust

present under normal operating conditions

II

1

combustible dust

through failure or abnormal operation of machinery

II

1

combustible dust

electrically conductive dust present

II

1

combustible dust

not normally at levels that can be ignited

II

2

combustible dust

through malfunctioning of handling equipment AND failure of electrical equipment

II

2

easily ignitible fibers or flyings

handled, manufactured or used

III

1

easily ignitible fibers or flyings

stored and handled (not manufactured or used)

III

2